Catching flathead catfish at peak spawn???

We've been doing really well this year with the flatheads, up until about 3 weeks ago. We can't seem to find them anywhere. We've picked up a few 5 to 10lbers here and there, but no big ones. Do any of you have any strategies for catching the big flatheads during the peak of the spawn??? I know it is possible to catch them. Some people in a tournament I fish brought in a limit of nice flatheads this weekend. I just can't seem to figure out where these big girls have went to. Is anybody on here having any luck for the flatties during the spawn? The weather here in SC has been hot/dry, surface water temp is around 83 degrees, and I'm fishing in a big resevoir.

I dunno where else to try. Where we fish the channel is 40 to 60ft deep. We've tried deep structure, channel bends, the upper and lower edges of the channel, shallow water structure, Rocky points, riprap, shallow flats. The few flatheads we are catching are coming pretty shallow 10 to 15ft deep, and near rip rap. But none of these cats are over 10lbs.

One of the things thats goin on Clarkhill is the thermocline is around 15 foot deep.There is nothing any deeper than that so I started fishing the biggest rocks around islands in shallow water close to deep water.This could be goin on at Hartwell too.Has your bait been dieing after about 15 to 20 minutes if it is, thats probably whats goin on.I still hadnt caught any over 20lbs in the last 3 weeks though.